1. Field of the Invention
This invention relates to a process suitable for forming a functional deposited film containing silicon, particularly a polycrystalline silicon deposited film for use in semiconductor devices, photosensitive device, line sensors for image input, image pick-up devices, etc.
2. Related Background Art
Heretofore, a process for forming a polycrystalline or monocrystalline semiconductor layer composed of coarse grains by exposing a polycrystalline or amorphous semiconductor layer on an insulating substrate to an energy beam has been proposed as prior art. For example, a polycrystalline or monocrystalline silicon layer composed of coarse grains can be formed by coating a silicon substrate with an insulating film of SiO.sub.2 or SiN, depositing a polycrystalline layer thereon by CVD in reduced pressure or normal pressure or by plasma CVD, and subjecting the polycrystalline layer to annealing by irradiation of a continuous laser beam or electron beam. However, it is difficult to control crystal grain size, crystal grain size distribution, crystal grain site, etc. of polycrystalline silicon or crystal face orientation according to the prior art process. Therefore, in semiconductor devices where semiconductor elements are formed on a semiconductor substrate as described above, fluctuation and reliability in their characteristics have been thus problems. According to another prior art process, a polycrystalline layer composed of coarse grains or a monocrystalline layer is formed by forming regular grooves (gratings) on an insulating film surface, depositing a polycrystalline or amorphous silicon layer thereon, and annealing the layer (graphoepitaxial process). However, this process has a poor reproducibility and the crystal face orientation cannot be completely controlled. Thus, a novel process for, depositing a film free from these problems has been desired.